This invention relates to a tiltable, portable, pivotable marine type ladder. More particularly, this invention concerns a tilting marine type ladder which is normally in a horizontal position out of the water and when a slight amount of vertical force is applied the ladder tilts into a vertical position into the water; on release of such force, the ladder automatically tilts back to its initial horizontal position.
The main use for tilting ladders is derived from their ability to be normally in one position, for example, a horizontal position, when not in use and tiltable to another position, for example, a vertical position, when required for use. Up until the last decade, tilting ladders were generally utilized for fire escapes (see U.S. Pat. Nos. 705,042; 712,262; 971,276; 1,009,241; 1,411,438; 1,482,117) or as balcony type stairs (see U.S. Pat. No. 1,140,833). Fire escape ladders and the like are unsuitable for marine type use due to their large number of stairs and their inability to be positioned in a variety of angles, especially in a vertical position. Fire escapes were generally constructed so that the stairs when released would be at an angle of about 45.degree. from the vertical to assist people in walking from one flight to a flight below.
With the recent utilization of fire-proof construction of high rise buildings, fire escapes are no longer required. A major employment of tilting stairs now is in the marine field as boat, dock and swimming pool ladders.
In the past, many marine type ladders have provided boaters and swimmers with means for climbing from a boat onto a stationary pier or dock. Such ladders have been rigidly secured to the piers, docks, boats or pool sides and therefore they were partially submerged in the water. The lower part of such ladders were subject to marine growth which necessitated periodic maintenance on the ladders. Various types of expensive gang planks and moving ladder devices have been designed to connect boats and docks to alleviate this problem.
In order to overcome the aforementioned problems, some workers in the art have resorted to retractable and movable type marine ladders which require some considerable physical force in order to raise and lower the ladder. (See U.S. Pat. Nos. 3,285,367; 3,539,033; 3,606,934; 3,973,646 and British Patent Specification 743,995). Several conventional marine type ladders are disclosed in the 1973 Marine Catalog, Castle Harbor Ship Chandler, St. Mihiel Drive, Delran, N.J. pp. 92-95.
U.S. Pat. No. 2,721,345 discloses a boat stairs employing counterbalance pull springs 30. The springs serve to substantially counter balance the weight of the stairway 17 in its movement from its operative to its stored position.
U.S. Pat. No. 4,067,412 concerns a floating ladder having a rigid guide assembly for holding a ladder. The ladder has a floating bottom. The guide assembly allows for the vertical movement of the ladder as the water level rises and falls.
Heretofore there has been no marine type ladder that has an initial horizontal position out of the water which upon application of a slight vertical downward force automatically tilts into a vertical position to be submerged in the water and automatically reverts back to its initial position upon release of such force and upon activation by the water.